Truck-deployed nuclear reactors antineutrino detector: range?

[xpell]

Hi! I was reading this article about the possibility of detecting removals of "double-use" fissile materials from a known reactor using an antineutrino detector deployed in a truck "that uses 20 tons or less of scintillator material (and) could be fit into a 6-meter shipping container and parked outside (the) reactor building, roughly 19 meters from the core." Any other document I've checked (like this one and this one) also talks about detectors located very close to the reactors (max. 20 meters or so.) I find this a bit lame, since if the "customers" let you in so close to the reactor, you'll probably be able to inspect the reactor itself at will too. If they just don't let you in or they disable the detector (hey, it's in their property...) or somehow mess with it (using an additional "fake" antineutrino source, for example?), not to mention if you're trying to locate clandestine reactors from some distance, I think this technology in its current state-of-the-art is essentially useless for this purpose.

So, out of curiosity, I was wondering if those are just prototypes and it would somehow be possible to detect the antineutrinos from, let's say, at least a few hundred meters or kilometers, maybe deploying the detector in a larger truck / container or fitted into a more massive vehicle (a submarine for example, to detect the reactors of other nearby submarines.) Could this be achieved or it's totally off-limits of our present science or technology? And what about directionality?

BTW, this PROSPECT experiment talks about HEU reactors to set some limits. Would HEU reactors (like those on board the submarines and aircraft carriers) emit more antineutrinos when operating, please?

Thank you in advance!

 

[mathman]

Try nuclear engineering forum.

I am not sure what you have in mind by inspecting the reactor itself. Reactors give off deadly radiation - that's why (one of several reasons) you can't get inside the reactor building.

 

[xpell]

Try nuclear engineering forum.

I am not sure what you have in mind by inspecting the reactor itself. Reactors give off deadly radiation - that's why (one of several reasons) you can't get inside the reactor building.

Well, I meant inspecting the reactor (and the facility) just as the IAEA usually does. I'm sure they know well the appropriate procedures to safeguard them.

Anyway, I'm far more interested in this idea of "transportable" antineutrino detectors than in the specifics of nuclear engineering (in this occassion!), that's why I asked in this forum. I'd truly be fascinated if such kind of "mini-detectors" (instead of the large ones) could have any chance of locating a nuclear reactor from let's say a few kilometers away and provide some directionality with current or near-future science and technology. I'd be comfortable with a "back of the envelope" estimation (which I'd do myself if I knew how to!), no need to enter any kind of "swampy grounds."

 

[mfb]

To measure the amount of plutonium in a reactor without constant surveillance, you would have to take it apart and analyze the components. Quite impractical.

A larger distance is problematic. Even if background would be negligible (it is not), the mass has to go up with the square of the distance to get the same count rate. 20 tons at 20 meters distance, 500 tons at 100 meters distance, 50,000 tons at 1 km distance.
As comparison: Super Kamiokande has 50,000 tons (ultrapure water, not more expensive scintillator material).

 

[xpell]

To measure the amount of plutonium in a reactor without constant surveillance, you would have to take it apart and analyze the components. Quite impractical.

A larger distance is problematic. Even if background would be negligible (it is not), the mass has to go up with the square of the distance to get the same count rate. 20 tons at 20 meters distance, 500 tons at 100 meters distance, 50,000 tons at 1 km distance.
As comparison: Super Kamiokande has 50,000 tons (ultrapure water, not more expensive scintillator material).

Thank you very much as usual, Mfb. I have just found this paper answering most of my questions, but thanks a lot anyway.

I would still be interested in learning if a HEU reactor generates more antineutrinos than LEU reactors, but it's a secondary question.

 

[mfb]

The news article is based on this paper, which frequently cites earlier work from nearly the same team for the theory.
Enrichment enhances the sensitivity to plutonium production (see figure 2). It's not just a counting experiment, spectroscopy is needed to disentangle the different processes.

 

[QuantumPion]

From the article:

"By measuring the number of antineutrinos produced and their energy spectrum, researchers can calculate reactor power and the amount of uranium and plutonium isotopes in the core. So an antineutrino detector would reveal if plutonium was removed or more uranium was added, even if the monitoring was interrupted for a period and then restarted."

I find this hard to believe. I'm not saying it's impossible, but I cannot fathom how it is done. Antineutrinos are produced by beta decay of fission products. The fission products of U-235 and Pu-239, while not identical, are very similar and overlap. I'm amazed/skeptical they can detect neutrinos with enough precision to be able to distinguish the difference between two, and with low enough uncertainty to determine small changes in core fuel composition.

 

[Vanadium 50]

I find this hard to believe

You do know that this has already been done, at Bugey way back in the 1990's. This was a major systematic at KamLAND (which looked at 53 reactors, which limited their ability to control this).

What is new is that there is now enough understanding of neutrino oscillations to ensure that you can do the measurement from a truck parked nearby and that there are now detector technologies that could conceivably fit on a truck.

 

[QuantumPion]

Oh I see. From this paper: http://arxiv.org/abs/1101.2663 - They measured the beta spectrum to infer the neutrino spectrum and built a database based on that from various reactors. Makes sense.

 

[Vanadium 50]

Well, I meant inspecting the reactor (and the facility) just as the IAEA usually does.

The IAEA almost never inspects reactors. A reactor doing nefarious things looks pretty much the same as one that does not. They mostly inspect paperwork.

 

[QuantumPion]

edit: nevermind, found some relevant papers.